Incorrect Condition for Thermal Stress in a Body

Thermal stress in a body occurs due to the difference in temperature between the different parts of the body. When a body is subjected to a change in temperature, it expands or contracts depending on its coefficient of thermal expansion. This change in dimension can lead to internal stresses within the body, which can cause deformation or even failure. However, not all conditions affect thermal stress in a body. The incorrect condition for thermal stress in a body is discussed below.

Modulus of Rigidity

Modulus of rigidity is a measure of a material's resistance to shear deformation. It is defined as the ratio of shear stress to shear strain. The modulus of rigidity is an important property of materials that are subjected to torsional or shearing loads. However, it does not affect thermal stress in a body. Thermal stress is caused by the difference in temperature between the different parts of a body, and it is affected by the following conditions:

Coefficient of Thermal Expansion

The coefficient of thermal expansion is a measure of a material's response to changes in temperature. It is defined as the fractional change in length or volume of a material per unit change in temperature. Materials with a high coefficient of thermal expansion tend to expand more when subjected to a change in temperature. This can lead to thermal stress in a body.

Temperature Rise

Temperature rise is the change in temperature between the different parts of a body. When a body is subjected to a temperature rise, the parts of the body that are closer to the heat source tend to expand more than the parts that are further away. This can lead to thermal stress in a body.

Modulus of Elasticity

The modulus of elasticity is a measure of a material's stiffness. It is defined as the ratio of stress to strain in a material when subjected to an external force. Materials with a high modulus of elasticity tend to resist deformation more when subjected to external forces. This can affect the thermal stress in a body.

Conclusion

In conclusion, the incorrect condition for thermal stress in a body is the modulus of rigidity. Thermal stress is caused by the difference in temperature between the different parts of a body and is affected by the coefficient of thermal expansion, temperature rise, and modulus of elasticity. Understanding these conditions is important in designing structures and components that can withstand thermal stress.